1. Field of the Invention
The invention relates to numerical control (NC) program creating devices.
2. Description of the Related Art
NC programs for operating machine tools are sequential programs. Accordingly, the program proceeds to the subsequent process after one process is completed. For example, in the case of starting cutting after setting the spindle speed to a predetermined command value, a non-cutting feed code G00 for a feed mechanism in a non-cutting state, in which a cutting start position is a command position, is placed after a spindle rotation code M03, and a cutting feed code G01 for the feed mechanism in a cutting state is placed after the non-cutting feed code G00.
An operation of changing tools is performed after a spindle is moved to a prescribed position in the non-cutting state. Accordingly, an automatic tool changer (ATC) code (tool change code) M06 is placed after a non-cutting feed code G30 (or G00). The ATC code is a code for performing a series of operations, namely the operations of opening a shutter of an automatic tool changer, changing tools, and closing the shutter.
In the case of starting cutting after indexing a rotating workpiece mount table (rotary table) to a desired angle, a code for unclamping the rotary table, a code for indexing the rotary table to the desired angle, and a code for clamping the rotary table are sequentially placed in this order, the non-cutting feed code G00 is placed after the code for clamping the rotary table, and the cutting feed code G01 is placed after the non-cutting feed code G00. The NC programs are described in, e.g., Japanese Patent Application Publication Nos. 2008-112217 (JP 2008-112217 A) and 2013-114425 (JP 2013-114425 A).
As described above, the non-cutting feed code is not executed simultaneously with the operation of changing the spindle speed, the series of operations for changing tools, and the operation of clamping the rotary table, but is executed independently before or after the operation of changing the spindle speed, the series of operations for changing tools, and the operation of clamping the rotary table. Namely, the non-cutting feed code and the codes for the operation of changing the spindle speed, the series of operations for changing tools, and the operation of clamping the rotary table are sequentially executed one by one. Accordingly, the machining cycle time can be reduced if at least part of the codes can be executed simultaneously.